Nozzle chest attachment



Oct. 22, 1940. H, P DAHLSTRND v 2,218,788A

NozzLE CHEST ATTACHMENT Filed NOV. 26, 195'7 Patented Oct. 22, 1940 PAT-ENT 'oFFicE No'zzLn CHEST ATTACHMENT Hans P. Dahlstrand, Wauwatosa,Wis., assigner .l

)to Allis-Chalmers Manufacturing Company,

Milwaukee, Wis., a corporationof Delaware` rApplication November 26, A1937, Serial No. 176,411 J l 6 Claims.

This invention relates to high temperature turbine construction and particularly toV a means for introducing steam toa turbine in such manner as to minimize the effect of high 'temperature on the .casing thereof.

It is an object of this invention to provide a means for attaching a nozzle chest to a turbine casing whereby transfer of heat from the nozzle chest to the casingis reduced.

Further objects of this invention are: the provision of an improved means for introducing high temperature steam into a turbine casing;

' the provision of a welded connection between the turbine casing and nozzle chests located therein; the provision of a neck portion extending outwardly from the turbine cylinder, the nozzle chest kbeing attached to the outer end of said neck portion; and a unitary connection between a steam inlet pipe, the turbine casing and the nozzle chest, or between a steam valve body, the turbine casing and the nozzle chest.4

It has heretofore been common practice to provide a flanged connection between the steam inlet pipe or valve body and turbine casing, and between the casing and nozzle chest. of an impulse or an impulse reaction turbine. Because of the high temperature of the steam introduced into the turbine and the large area of contact between steam inlet pipe and turbine casing provided by such flanged connection, sufcient heat was transferred to the'casing at the point of steam inlet to produce excessive local expansion which resulted in distortion of the turbine cylinder. Another prior practice is to make the nozzle chest integral with the turbine casing. This also results in undesirable local heating of the cylinder, causing vdistortion thereof, accompanied by blade interference and steam leakage.

In accordance with the present invention, the

nozzle chests are welded to the turbine casing,

the weld being'preferably at a point spaced from the cylinder proper by a neck portion made integral with the cylinder. The weld may be utilized to connect a steam conduit, a nozzle chamber and the turbine casing at one welded joint; and the .cross-sectional area of the weld is preferably no greater thatn the cross-sectional area of the parts to be connected. In this way the joint is heated uniformly, avoiding distortion thereof; and the heat transfer area between the nozzle chest and the casing isreduced.

In the drawing, v v

Fig. 1 illustrates a preferred construction in accordance with this invention, showing an elevation sectional view of an impulse or impulseY v at the outer end of neck portions I8.

reaction, turbine taken 'in a plane perpendicular to the axis of the turbine, the'spindle of the turbine not vbeing shown. Y f

Fig. 2 isa fragmentary sectional elevation view of-a modified construction." 1

Referring to Fig. 1,-l a rgenerally cylindrical turbine casing I 0 is provided with a plurality of `individualnozzle chests II, I2, I3, each of whichv carries a plurality 4of removable nozzles I5. Each nozzle has an integral steam inlet 20. High temperature steam is admitted'to the turbine by means of steam pipes I4. The admission of steam may be regulated by hand valves I6 having Valve casings I'I, or the steam may be admitted into the nozzle chest Idirectly, as shown with respectto central nozzle chest I2.

To remove thepoints of steam inlet from contact with the casing II), nipples or neck portions I8, are provided oncasin'g I0 at points of steam admission, and nozzle chests Il, I2 and I3 are connected to inlet pipes I4 (or valve casings I1) This connection of nozzle chambers and steam inlets (or valve casings) to theouter end ofv neck portions I8 is preferably effected by means of welds I9. The welds notonly avoid the weight and dimculty of flange connections, but providea contact area of greatly reduced cross section between the highlyy heated valve body or steam pipe and nozzle chamber on theA one hand and the relatively cool-casing Ill on the other, thereby reducing heat transfer to the easing. The crosssectional area of the weld I9 is preferably not substantially larger than the cross-sectional area of the parts being -joined together, thereby reducingy the heat Atransfer areay between live steam and the turbine casing, and resulting in more uniform heating of the joint. Moreover, even if the outer end of neck portions I8 becomes hot, the expansion thereof does not result in high stresses in the main turbine casing Il). Since the heat from valve casing 'I1 or pipe I 4 must flow through the length of neck portion I8,

'only a relatively small proportion of the heat is steam conduit I4) either by a weld 22, or by a flanged connection. This indicates that it is not necessary to connect all three members (neck I8, nozzle chest inlet 2U and valve casing I1) by a single Weld in order to obtain some of the advantages of this invention.

While this construction has been described with reference to a steam turbine it is equally applicable to gas turbines, or any other case Where it is desired to lead a high temperature fluid into a casing Without causing undesirable distortion therein.

While the invention has been illustrated by a specific construction, it is not desired to limit the scope thereof except as dened by the claims appended hereto.

It is claimed and desired to' secure by Letters Patent:

1. In a turbine, a casing, a nozzle chest provided With a steam inlet and means for supporting said nozzle chest in said casing consisting of a Welded joint between said steam inlet and said casing, said Welded joint being the only area of close contact between said nozzle chest and said casing, whereby a reduced heat transfer area is obtained between said nozzle chamber and said casing.

2. In a turbine, a casing, a nozzle chest provided with a steam inlet and means for supporting said nozzle chest in said casing comprising a neck integral with said casing and extending therefrom and means consisting of a contact area not substantially greater than the cross-section area of said neck for supporting said nozzle chamber from the outer end of said neck, Whereby the heat transfer connection between said nozzle chest and said casing is increased in length and limited in cross-sectional area.

3. In a turbine, a casing, a nozzle chest provided with a steam inlet and means for supporting said nozzle chestin said casing consisting of a neck integral with said casing and extending therefrom and a single welded connection between said nozzle chest steam inlet and the outer end of said connection,

4. In a turbine, a casing, a nozzle chest mounted Within said casing, a conduit for admitting steam to the turbine, and a single Welded joint uniting said steam conduit, said nozzle chest and said casing.

5. A construction as claimed in claim 4, in which the cross-sectional area of the Welded joint is not substantially greater than the normal cross-sectional area-of said conduit.

6. In a turbine, a casing provided with a neck portion extending therefrom, a steam inlet valve body, a nozzle chest mounted in said casing, and a single welded connection joining the outer end of said neck portion with said valve body and said nozzle chest.

HANS P. DAHLSTRAND. 

